The GALILEO γ-ray array at the Legnaro National Laboratories Goasduff, A.; Mengoni, D.; Recchia, F. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
11/2021, Letnik:
1015
Journal Article
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Odprti dostop
GALILEO, a new 4π high-resolution γ-detection array, based on HPGe detectors, has been developed and installed at the Legnaro National Laboratories. The GALILEO array greatly benefits from a ...fully-digital read-out chain, customized DAQ, and a variety of complementary detectors to improve the resolving power by the detection of particles, ions or high-energy γ-ray transitions. In this work, a full description of the array, including electronics and DAQ, is presented together with its complementary instrumentation.
There is a large body of evidence that atomic nuclei can undergo octupole distortion and assume the shape of a pear. This phenomenon is important for measurements of electric-dipole moments of atoms, ...which would indicate CP violation and hence probe physics beyond the Standard Model of particle physics. Isotopes of both radon and radium have been identified as candidates for such measurements. Here, we observed the low-lying quantum states in
Rn and
Rn by accelerating beams of these radioactive nuclei. We show that radon isotopes undergo octupole vibrations but do not possess static pear-shapes in their ground states. We conclude that radon atoms provide less favourable conditions for the enhancement of a measurable atomic electric-dipole moment.
In the current work, 4 μm thick CrN/NbN coating utilising nanoscale multilayer structure with bi-layer thickness of Δ = 2.9 nm has been used to protect 9 wt% Cr steels such as P92 widely used in ...steam power plants. The uniquely layered coatings have a combination of nitrides of chromium and niobium which are not only resistant to aqueous corrosion and corrosion-erosion and have excellent tribological properties, but also have oxidation resistance in dry air up to a temperature of 850 °C. The novel High Power Impulse Magnetron Sputtering (HIPIMS) deposition technology has been used to deposit CrN/NbN with enhanced adhesion (critical load of scratch adhesion LC2 = 80 N) and a very dense microstructure as demonstrated by Transmission Electron Microscopy (TEM) imaging. These superior coating properties are achieved due to the unique high metal ion content (up to 90%) in the HIPIMS plasma, which allows particle acceleration and trajectory control by external electrical and magnetic fields thus delivering highly energetic material flux on the condensing surface.
P92 bare and coated samples were oxidised at 650 °C in 100% steam atmosphere up to 2000 h, in order to simulate the future operation conditions of steam turbines employed in power plants. The oxidation kinetics was evaluated by mass gain measurements. Under these conditions CrN/NbN provided reliable protection of the P92 steel. The paper also discusses the effect of growth defects and high temperature crack formation analysed by Scanning Electron Microscopy and Focused Ion Beam-Scanning Electron Microscopy techniques (SEM and FIB-SEM, respectively) on the high temperature corrosion resistance in pure steam atmosphere thus revealing the coatings potential failure mechanisms.
•Benefit of highly ionised metal plasma flux for coating deposition demonstrated.•CrN/NbN coating-superior corrosion resistance against high temperature steam shown.•CrN/NbN film-steel substrate protection mechanism under extreme condition described.•CrN/NbN coating degradation mechanism under high temperature steam attack revealed.
NEDA—NEutron Detector Array Valiente-Dobón, J.J.; Jaworski, G.; Goasduff, A. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
05/2019, Letnik:
927
Journal Article
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The NEutron Detector Array, NEDA, will form the next generation neutron detection system that has been designed to be operated in conjunction with γ-ray arrays, such as the tracking-array AGATA, to ...aid nuclear spectroscopy studies. NEDA has been designed to be a versatile device, with high-detection efficiency, excellent neutron-γ discrimination, and high rate capabilities. It will be employed in physics campaigns in order to maximise the scientific output, making use of the different stable and radioactive ion beams available in Europe. The first implementation of the neutron detector array NEDA with AGATA 1π was realised at GANIL. This manuscript reviews the various aspects of NEDA.
The multinucleon transfer (MNT) reaction approach was successfully employed for the first time to measure the isomeric ratios (IRs) of \(^{211}\)Po (25/2\(^+\)) isomer and its (9/2\(^+\)) ground ...state at the IGISOL facility using a 945 MeV \(^{136}\)Xe beam impinged on \(^{209}\)Bi and \(^{\rm nat}\)Pb targets. The dominant production of isomers compared to the corresponding ground states was consistently revealed in the \(\alpha\)-decay spectra. Deduced IR of \(^{211}\)Po populated through the \(^{136}\)Xe+\(^{\rm nat}\)Pb reaction was found to enhance \(\approx\)1.8-times than observed for \(^{136}\)Xe+\(^{209}\)Bi. State-of-the-art Langevin-type model calculations have been utilized to estimate the spin distribution of an MNT residue. The computations qualitatively corroborate with the considerable increase in IRs of \(^{211}\)Po produced from \(^{136}\)Xe+\(^{\rm nat}\)Pb compared to \(^{136}\)Xe+\(^{209}\)Bi. Theoretical investigations indicate a weak influence of target spin on IRs. The enhancement of the \(^{211}\)Po isomer in the \(^{136}\)Xe+\(^{\rm nat}\)Pb over \(^{136}\)Xe+\(^{209}\)Bi can be attributed to the different proton (\(p\))-transfer production routes. Estimations demonstrate an increment in the angular momentum transfer, favorable for isomer production, with increasing projectile energy. Comparative analysis indicates the two entrance channel parameters, projectile mass and \(p\)-transfer channels, strongly influencing the population of the high-spin isomer of \(^{211}\)Po (25/2\(^+\)). This work is the first experimental and theoretical study on the IRs of nuclei produced via different channels of MNT reactions, with the latter quantitatively underestimating the former by a factor of two.
Abstract
The
$$\beta $$
β
-delayed
$$\gamma $$
γ
spectroscopy of
$$^{81}$$
81
As has been performed using a purified beam of
$$^{81}$$
81
Ge
$$(9/2^+)$$
(
9
/
2
+
)
ground state at the Ion Guide ...Isotope Separator On-Line facility (IGISOL). The
$$^{81}$$
81
Ge
$$^+$$
+
ions were produced using proton-induced fission of
$$^{232}$$
232
Th and selected with the double Penning trap JYFLTRAP for the post-trap decay spectroscopy measurements. The low-spin
$$(1/2^+)$$
(
1
/
2
+
)
isomeric-state ions
$$^{81m}\hbox {Ge}^+$$
81
m
Ge
+
were not observed in the fission products. The intrinsic half-life of the
$$^{81}$$
81
Ge ground state has been determined as
$$T_{1/2}=6.4(2)~\hbox {s}$$
T
1
/
2
=
6.4
(
2
)
s
, which is significantly shorter than the literature value. A new level scheme of
$$^{81}$$
81
As has been built and is compared to shell-model calculations.
Background and importanceGlycaemic alterations are highly prevalent in premature newborns during the first days of life. Particularly, hyperglycaemia has been reported as an independent risk factor ...for increased mortality and morbidity. This condition requires the use of insulin infusions for its treatment. However, this drug presents problems of adsorption to plastic that is intensified with low insulin concentrations and infusion rhythms used in neonates, conditioning the decrease and also the ignorance of the doses actually administrated to the newborn. There is no consensus on the appropriate insulin preparation and administration.Aim and objectivesTo determine the combination of variables for the preparation and administration of insulin infusions that provides higher accuracy and lower probability of error.Material and methodsAn experimental study was carried out with the aim of determining which variable (additive (albumin yes/no), solution (sodium chloride solution, NaCl 0.9%/glucose 5%), operator (1/2), preconditioning (yes/no), purge (yes/no), concentration (0.05–0.1 UI/mL), infusion rate (0.3–0.7 mL/h) and infusion duration (1 hour/24 hours)) most influences the concentration and dose of insulin administrated. The determinations were made with immunoassay using IMMULITE 1000 equipment. Previously, an ad hoc calibration was developed, adjusted to the range of doses commonly used in neonatal insulin infusions. Finally, a screening model using Plackett-Burman designs was developed to calculate insulin recovery and determine the variables with the most influence.Results24 experimental infusions were made, using combinations of different variables. After analysing the total of the samples, each of the recovery values obtained were entered in the screening model. The variables that achieved higher insulin recovery values were the additive (albumin - yes) and the solution (NaCl 0.9%). The model can explain 48.16% of the variation in insulin recovery, in which the additive has a standardised effect four times greater and the solution two times greater than the rest of the variables that do not exceed 1. (Figure 1: Pareto diagram)Conclusion and relevanceThe additive and the solution seem to be the most important determining factors for the recovery of insulin in the preparation of the infusions. The addition of albumin and preparing the infusions with sodium chloride solution 0.9% as solution results in a greater recovery of insulin.References and/or acknowledgementsConflict of interestNo conflict of interest
Abstract
The discrepancy between shell-model calculations and intermediate-energy Coulomb excitation measurements in
46
Ar still stands as an unsolved puzzle in understanding the
N
= 28 shell ...evolution. This phenomenon has significant relevance considering the remarkable achievements of the shell model and the SDPF-U interaction in the region which is able to predict the fading of the
N
= 28 shell gap in neutron-rich
44
S. Recent measurements narrowed down this discrepancy to an overestimation of the proton amplitude to the quadrupole transition matrix element. The current work aims to propose a different perspective on the puzzle, by studying a direct proton-transfer reaction on
46
Ar as a means to directly probe the proton wavefunction of the ground state this isotope. By measuring the amount of
l
= 0 transfer to the ground state (1/2+) of
47
K with respect to the
l
= 2 to the first excited state (3/2+), we aim to gain insight into the ground state proton wavefunction of
46
Ar. We will present a brief description of the experiment performed at the SPIRAL1 facility in GANIL (France). The experimental apparatus allowed a full reconstruction of the two-body reaction thanks to the combination of AGATA, VAMOS, MUGAST, CATS2, and HECTOR.
IR spectra provide valuable information about biological systems and can be obtained with compactable and affordable instruments, but the lack of sensitivity of this technique hampers its use in the ...determination of drugs in clinical fluids. Taking lidocaine as a target molecule, in this paper we introduced a methodology for determining drugs in urine samples using infrared spectroscopy. The lack of sensitivity of the IR was compensated with the combination of an effective and straightforward dispersive liquid–liquid microextraction and the measurement of the dry film of the organic extracts through attenuated total reflectance (ATR). The method developed improves the sensitivity by eliminating the solvent and preconcentrating the analyte in the surface of the ATR crystal. Urine samples were taken from 15 volunteers, and 9 samples were spiked at 6 concentration levels ranging from 0 to 33mgL−1. Multivariate models based on partial least squares regression and science-based calibration were performed and validated with a separated set of spiked urine samples from other patients, obtaining ratio prediction to deviation (RPD) values higher than 3.5. The limit of detection values obtained were 0.5mgL−1 for the univariate calibration and 1.7mgL−1 for a reliable multivariate calibration. Therefore, the procedure is limited to only levels of lidocaine higher than 2mgL−1 but serves as an untargeted, fast, and versatile screening tool, which maintains all the advantages of the widespread application of the IR spectroscopy to the clinical analysis, such as simplicity, compactability, and minimum use of reagents and solvents.
•FTIR sensitivity was enhancement by dispersive microextraction•Infrared spectroscopy was applied to lidocaine determination in urine•Urine matrix effect in FTIR lidocaine determination was studied•Proposed method provides a green alternative to determine lidocaine at low concentration levels
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